1. Field of the Invention
The present invention relates to image display devices, and more particularly, to a method for setting a compensation region for an irregular defect region in an image display device, which can set a compensation region by applying the same algorithm regardless of kinds of irregular display defects.
2. Discussion of the Related Art
Currently, as the image display devices, flat display devices, such as liquid crystal display device LCD, plasma display panel PDP, organic light emitting diode OLED, are used, mostly.
The image display device passes through an inspection process for detecting a display defect after finishing fabrication of a display panel which is to display an image. Though the display panel having the display defect detected in the inspection process passes through a repair process for the defective portion, there is the display defect that can not be repaired even by the repair process.
The display defect is caused mostly by variation of exposure quantity come from superimposition of the exposures and aberration of multi-lens at the time of multi-exposure by an exposing apparatus used in a thin film pattern forming process. The variation of exposure quantity causes variation a width of the thin film pattern, to vary parasitic capacitance of the thin film transistor, a height of a column spacer which maintains a cell gap, and parasitic capacitance between signal lines. The variations cause brightness variation, resulting to display a regular display defect in a form of horizontal lines or vertical lines. Following reduction of a gap between the liquid crystal display panel and a back light unit for making the liquid crystal display device slimmer, the regular display defect can be displayed, which has a form of horizontal lines corresponding to locations of a plurality of lamps due to shortage of a light diffusion path. In the display defect, there are, not only the regular display defect, but also an irregular defect caused by a defective process, such as infiltration of foreign matters, pinholes, or so on. Because the regular and irregular defects can not be solved by improvement of the process technology, a method is taken into consideration recently, in which brightness of a display defect region is compensated by a data compensating method.
In order to compensate brightness of the display defect region by the data compensating method, a work is required, in which a compensation region for the display defect region detected in the inspection process is set appropriately, and a compensation data is set appropriately taking a difference of brightness between the compensation region and a non-compensation region (i.e., a normal region) into account.
In the meantime, since the irregular defect regions has a variety of shapes compared to the regular defect regions, a work for setting position information on the irregular defect regions, i.e., coordinate information is difficult. For an example, a method for extracting a boundary coordinate along a boundary of the irregular defect region by clicking a mouse has problems in that operation is complicate, and a long time period is required, because there are lots of coordinates to be set, and the operation of setting the coordinate information varies with shapes of the irregular defect regions. Moreover, since there is no reference for a method for setting the boundary coordinates of the irregular defect region, to set the compensation region varied with operators, matching between the defect region and the compensation region becomes poor.
Moreover, the irregular defect region requires a large amount of coordinate information compared to the regular defect region. Consequently, if the coordinate information on the irregular defect region and the coordinate information on the regular defect region are stored in spaces of a memory different from each other respectively, a problem of increased memory capacity takes place.